EP0072610A2 - Integral Abbrems- und Auskuppelgetriebe - Google Patents

Integral Abbrems- und Auskuppelgetriebe Download PDF

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Publication number
EP0072610A2
EP0072610A2 EP82303234A EP82303234A EP0072610A2 EP 0072610 A2 EP0072610 A2 EP 0072610A2 EP 82303234 A EP82303234 A EP 82303234A EP 82303234 A EP82303234 A EP 82303234A EP 0072610 A2 EP0072610 A2 EP 0072610A2
Authority
EP
European Patent Office
Prior art keywords
drive shaft
coil spring
spring
rotation
drive cylinder
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP82303234A
Other languages
English (en)
French (fr)
Other versions
EP0072610A3 (de
Inventor
Louis J. Vassos
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Skil Corp
Original Assignee
Skil Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Skil Corp filed Critical Skil Corp
Publication of EP0072610A2 publication Critical patent/EP0072610A2/de
Publication of EP0072610A3 publication Critical patent/EP0072610A3/de
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q11/00—Accessories fitted to machine tools for keeping tools or parts of the machine in good working condition or for cooling work; Safety devices specially combined with or arranged in, or specially adapted for use in connection with, machine tools
    • B23Q11/0078—Safety devices protecting the operator, e.g. against accident or noise
    • B23Q11/0092—Safety devices protecting the operator, e.g. against accident or noise actuating braking or stopping means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27B—SAWS FOR WOOD OR SIMILAR MATERIAL; COMPONENTS OR ACCESSORIES THEREFOR
    • B27B5/00—Sawing machines working with circular or cylindrical saw blades; Components or equipment therefor
    • B27B5/29—Details; Component parts; Accessories
    • B27B5/38—Devices for braking the circular saw blade or the saw spindle; Devices for damping vibrations of the circular saw blade, e.g. silencing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D49/00—Brakes with a braking member co-operating with the periphery of a drum, wheel-rim, or the like
    • F16D49/02—Brakes with a braking member co-operating with the periphery of a drum, wheel-rim, or the like shaped as a helical band or coil with more than one turn, with or without intensification of the braking force by the tension of the band or contracting member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D59/00—Self-acting brakes, e.g. coming into operation at a predetermined speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D67/00—Combinations of couplings and brakes; Combinations of clutches and brakes

Definitions

  • This invention relates generally to the field of power driven devices having a tool mechanism driven by a power source. More specifically, the invention is particularly, although not exclusively, suitable for use in hand-held power saws in which an operator can be injured in the event the lower blade guard is restrained from closing over the blade.
  • Circular saws are normally designed to be utilized by an operator grasping a handle portion of the housing which contains a trigger mechanism to control an electric motor. Should the primary blade safety device (lower guard) be restrained after the blade exits a workpiece, there will be no shield between the operator and the revolving blade. Should the operator allow the revolving blade to come in contact with his body, serious personal injury could result.
  • the primary blade safety device lower guard
  • a more specific object of the invention is to provide a coil spring decoupling mechanism for preventing the transmission of torque from the motor and associated gears to the blade of a saw when the trigger is released or the above described movement occurs.
  • a still further object of the invention is to provide a coil spring decoupling mechanism which, in addition to the function described above, will also act as a brake for stopping the rotating blade.
  • the present invention provides a power driven device of the type including a housing, a power source, and a tool mechanism driven by the power . source, the improvement in an integral brake and clutch comprising
  • the present invention provides a hand-held power saw of the type including a housing, a power source, and a blade means driven by the power source for sawing a workpiece, the improvement in an integral brake and clutch comprising:
  • a preferred embodiment of the invention is especially adapted for use with a circular saw which typically includes a housing, a motor, a manually operable switch for controlling the motor, and a drive shaft having a blade mounted thereto.
  • the integral brake and decoupling (clutch) mechanism which is a significant apparatus aspect of this invention, includes a tubular drive cylinder disposed concentric with and adjacent to the drive shaft. This drive cylinder is driven by the motor by means of gears.
  • a torque transmission element defined by a coil spring transfers torque from the drive cylinder to the shaft.
  • the axis of the spring is concurrent with the axis of the shaft.
  • the spring is disposed so that its periphery continuously engages a first cylindrical surface on the drive shaft and a second cylindrical surface on the drive cylinder.
  • the coil spring is dimensioned to exert a substantial predetermined force against these surfaces when no torque is being transmitted.
  • the spring is helically oriented such that the force it exerts on the drive shaft and drive cylinder increases with applied torque thereby locking the drive shaft and drive cylinder to the spring which rotates therewith during operation.
  • An acceleration detecting means senses an abrupt movement of the housing.
  • the brake and decoupling mechanism which is responsive to the release of the trigger and/or acceleration detecting means, stops the rotation of the coil spring preventing torque from being coupled to the drive shaft when the trigger is released and/or this movement sensed.
  • the friction between the spring and drive shaft operates as a brake to stop the rotation of the blade.
  • Figure 1 illustrates a circular saw 10 in engagement with a workpiece 12.
  • This saw includes a housing 14, and a handle portion 16 having a trigger 18 connected to a manually operable switch mechanism 20 for controlling the motor (not shown).
  • the housing also includes a guide member or base plate 22 for controlling the position of blade 24 relative to the workpiece 12.
  • the blade is connected to drive shaft 28 and is rotated in a direction as indicated by arrow 26.
  • an acceleration or inertia detecting means 32 includes a first arm 36 which is contoured to define a pawl 38 and a second arm 40 which extends substantially transverse of the first arm. These first and second arms define a bell crank 34. One end of the first arm is pivotally mounted to housing member 42 about pivot point 44. An aperture 45 in the housing is dimensioned to threadedly receive an insert 46. This insert mounts a ring magnet 48 attached thereto by conventional means. A slot for a screwdriver is provided in the outer end of insert 46 to allow its position to be adjusted.
  • the insert is made from a non-magnetic material, such as a plastic.
  • magnet 44 is to provide sufficient force, during normal operation of the saw, to maintain first arm 36 of the bell crank adjacent the magnet as indicated by the phantom position of the bell crank. At least a portion 35 of the first arm must be either made of or carry a material which can be attracted to magnet 44.
  • FIG. 1 diagrammatically illustrates the circular saw 10 in a generally horizontal orientation as shown in Figure 1.
  • blade 24, shaft 28 and a collar 50 will be rotating counterclockwise as indicated by arrow 26 in Figure 1 and arrow 52 in Figure 2.
  • pawl 38 of the first arm 36 will engage tooth (abutment member) 54 located on the perimeter of collar 50 to stop the rotation of the collar upon the detection of said movement. Stopping the rotation of collar 50 decouples the drive shaft 28 from the motor and initiates a braking action to stop the drive shaft and blade; how these results are achieved is described in detail below with reference to Figures 3-6.
  • the bell crank preferably is reset to its operative position, as indicated in phantom lines in Figure 2, by allowing spring-loaded trigger l8 to return to an extended or off position.
  • a conventional control cable 56 carries a slidable internal wire having one end connected to trigger 18 and the other end disposed adjacent to end 40a of second arm 40 of bell crank 34.
  • trigger l8 is retracted, as shown in solid lines, to activate the motor, the inner wire cable 56 is positioned to allow clearance with respect to short arm 40 permitting the bell crank to pivot from its operative position to an acceleration detecting position.
  • the inner wire of cable 56 engages end 40a of arm 40 to force the bell crank clockwise from the acceleration detecting position (if a movement had been detected) to its operative position thereby providing an automatic resetting function.
  • the other end 40b of the second arm of the bell crank may extend outwardly and be accessible for manual resetting.
  • the sensitivity of the acceleration detecting means 32 is dependent upon a number of factors including the shape,mass, pivot point location, and center of gravity of the bell crank, and by the magnitude of the magnetic attraction between magnet 44 and the bell crank. The magnitude of this magnetic attraction can be selectively varied by the positioning of insert 46.
  • FIGs 3 and 4 illustrate the preferred embodiment of the combined decoupling (or clutching) and braking mechanism 61.
  • Drive shaft 28 is mounted for rotation by bearings 60.
  • An annular wall 64 which is preferably an integral portion of the drive shaft, is concentric about the axis of the drive shaft and defines a continuous interior cylindrical surface 66.
  • the wall 64 is attached to the central portion 63 of the drive shaft by a disc- shaped flange portion 62.
  • a drive cylinder 68 is disposed coaxially about the drive shaft and adjacent wall 64.
  • Cylinder 68 defines a continuous interior cylindrical wall 70 preferably having a radius equal to the radius of cylindrical surface 66.
  • Surfaces 66 and 70 define a tubular chamber into which coil spring 72, also known as. a wrapped spring, is positioned.
  • the coil spring is preferably selected to have a diameter larger than that of the tubular chamber such that the spring is “squeezed" by surfaces 66 and 70. The difference in diameters results in what is commonly referred to
  • a small length of end 74 of coil spring 72 is bent parallel to the axis of the drive shaft.
  • a retaining collar 50 receives end 74 of the coil spring through a hole 76 in the collar. This collar is held in position by a snap ring 78. Retaining collar 50 and drive cylinder 68 would be free to rotate about the drive shaft if coil spring 72 were not present.
  • the drive shaft of the motor is coupled by gear 80 to drive cylinder 68 by means of conventional gear teeth 81.
  • a cutting blade 24, as shown in Figure 1, is attached by conventional means to the central portion 63 of the drive shaft.
  • the mechanism as shown in Figures 3 and 4 functions as a "one-way clutch" to couple torque from the drive cylinder 68 to the drive shaft 28.
  • drive cylinder 68 rotates clockwise as shown in Figure 3.
  • right-hand helical orientation of the coil spring is used.
  • the friction between the external surfaces of the coil spring in contact with cylindrical surface 70 causes the spring to tend to expand thereby increasing the force of the spring on surfaces 66 and 70.
  • the coil spring produces a radially outward force against cylindrical surfaces 66 and 70 to lock the drive shaft 28 and the drive cylinder 68 to the spring.
  • torque is being transmitted from the motor to the blade,the drive shaft, drive cylinder, coil spring, and retaining collar rotate in unison.
  • the coil spring functions as a clutch element to provide a torque transmission link from the drive cylinder to the shaft.
  • the spring is preferably constructed from a wire having at least one planar outer face and wound such that the planar face will engage surfaces 66 and 70 thereby increasing the contacting surface area of the spring.
  • the spring could be formed from a wire not having such a planar face.
  • the preferred embodiment of the decoupling and braking mechanism 61 also functions as a brake to stop the blade in the event of an abrupt movement of the housing.
  • the trigger 18 will be retracted to apply power to the saw as the latter engages a workpiece.
  • the end of wire 56 will be spaced from arm 40a.
  • the bell crank 34 of acceleration detecting means 32 pivots counterclockwise causing pawl 38 to engage tooth 54 of the retaining collar 50. Upon this engagement,notating collar 50 is substantially instantaneously stopped which then causes the coil spring to cease rotation since the tab end 74 of the spring is secured to the collar.
  • FIGS 5 and 6 illustrate an alternative embodiment of an integral clutch and brake mechanism 91 utilizing a coil spring as the torque transmission element.
  • a drive shaft 90 is rotatably held by bearings 92. A portion of the drive shaft accepts a saw-blade secured thereto by conventional means.
  • the drive shaft includes extended diameter section 94 and a second extended diameter section 96 having an exterior cylindrical surface 98.
  • a drive cylinder 100 which is driven by a motor via gear 102, is mounted axially about shaft 90.
  • a reduced diameter portion 106 of the drive cylinder includes an exterior cylindrical surface 108 which is adjacent to cylindrical. surface 98.
  • a coil spring 110 axially engages cylindrical surfaces 98 and 108 and includes an end portion 112 which projects radially outward.
  • the spring coil 110 is preferably selected to have an interior diameter slightly less than the increased diameter portion 96 of the shaft. When the coil spring is placed in operative engagement as shown in Figure 6, it will exert a substantial predetermined force against cylindrical surfaces 98 and 108.
  • a tubular retaining collar 114 is disposed axially adjacent the coil spring and includes an aperture for receiving the end portion 112 of the coil spring.
  • This retaining collar also includes a tooth 116 disposed to project radially outwardly for engagement with a pawl such as is provided by the acceleration detecting means 32 as illustrated in Figure 2.
  • a snap ring 118 serves to locate drive cylinder 100 laterally with respect to shaft 90.
  • the drive train from the motor is coupled to the blade via cylindrical collar 100, coil spring 110, and drive shaft 90.
  • the coil spring 110 serves as the torque transmission element linking the drive cylinder to the shaft.
  • the drive cylinder, coil spring, retaining collar and shaft rotate in unison.
  • pawl 38 engages tooth 116 to stop the rotation of retaining collar 114 thereby stopping the rotation of coil spring 110 which substantially instantaneously decouples the shaft from the applied driving torque.
  • the friction between the coil spring and cylindrical surface 98 of the shaft serves as a brake to stop the rotation of the shaft and the blade attached thereto.
  • Overriding torque is defined herein as the torque (frictional force) between the coil spring and a surface in contact therewith when such surface rotates relative to the spring in a direction that loosens the grip of the spring.
  • Overriding torque exists between coil spring 72 and surface 66 of annular wall 64 of the drive shaft when the drive shaft rotates clockwise (note Figure 3) relative to the spring. This would occur upon the detection of a movement by the accleration detecting means 32 wherein the rotation of the spring would be stopped and the shaft (and blade) would continue to rotate due to inertia.
  • the mechanisms embodying the present invention are dimensioned to provide a high overriding torque in order to stop the rotation of the blade quickly.
  • An additional benefit derived from the present invention is that since the drive cylinder, gears and motor armature are immediately decoupled from the drive shaft upon the sensing of a movement, the brake need dissipate less energy and provide less braking torque in order to stop the blade in a given amount of time than would be the case if such decoupling had not occurred. For example, in order to stop the blade in 0.5 second from a no-load speed in a typical circular saw without the mechanism of the present invention, approximately 6.6 Newton meters of braking torque would be required and 900 joules of energy would have to be dissipated.
  • Another advantage of this invention is that simultaneously with decoupling the inertia associated with the motor and gears, a braking action is applied to stop the rotation of the blade. Hence, there is no significant time delay between decoupling and the application of the braking force upon the detection of an abrupt movement of the housing.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Forests & Forestry (AREA)
  • Sawing (AREA)
  • Braking Arrangements (AREA)
EP82303234A 1981-06-22 1982-06-22 Integral Abbrems- und Auskuppelgetriebe Withdrawn EP0072610A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US27597281A 1981-06-22 1981-06-22
US275972 1981-06-22

Publications (2)

Publication Number Publication Date
EP0072610A2 true EP0072610A2 (de) 1983-02-23
EP0072610A3 EP0072610A3 (de) 1984-05-30

Family

ID=23054583

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82303234A Withdrawn EP0072610A3 (de) 1981-06-22 1982-06-22 Integral Abbrems- und Auskuppelgetriebe

Country Status (2)

Country Link
EP (1) EP0072610A3 (de)
JP (1) JPS5871109A (de)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2570017A2 (fr) * 1983-12-20 1986-03-14 Tony Stempniakowski Detecteur electronique de contact de securite
EP0235670A3 (en) * 1986-03-06 1989-03-08 Gmbh & Co. Metabowerke Portable motorized chain saw with a friction brake for braking the saw chain
FR2739586A1 (fr) * 1995-10-06 1997-04-11 Gaubert Ets Dispositif de securite pour scie circulaire
EP2017045A3 (de) * 2007-07-20 2010-12-29 Husqvarna UK Limited Kettensäge
WO2013086584A1 (en) * 2011-12-15 2013-06-20 Furmanite Australia Pty. Ltd Improvements in machining apparatus
US9599170B1 (en) 2010-06-21 2017-03-21 Hydro-Gear Limited Partnership Electric motor clutch/brake assembly
EP3412392A1 (de) * 2017-06-09 2018-12-12 Andreas Stihl AG & Co. KG Handgeführtes arbeitsgerät mit einem werkzeug und einer bremseinrichtung für das werkzeug
EP3587038A1 (de) * 2018-06-26 2020-01-01 C. & E. Fein GmbH Getriebekopf und handwerkzeugmaschine
US11374473B2 (en) 2018-11-05 2022-06-28 C. & E. Fein Gmbh EC motor for an electric hand tool and method for producing a rotor for an EC motor
CN116601404A (zh) * 2020-12-10 2023-08-15 赛峰起落架系统公司 具有集成式停泊制动器的致动器

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3067597A (en) * 1961-09-27 1962-12-11 Black & Decker Mfg Co Over-riding safety coupling for spindle of power-driven tool
US3837450A (en) * 1972-11-06 1974-09-24 W Malion Clutch brake mechanism with a lost motion connection

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2570017A2 (fr) * 1983-12-20 1986-03-14 Tony Stempniakowski Detecteur electronique de contact de securite
EP0235670A3 (en) * 1986-03-06 1989-03-08 Gmbh & Co. Metabowerke Portable motorized chain saw with a friction brake for braking the saw chain
FR2739586A1 (fr) * 1995-10-06 1997-04-11 Gaubert Ets Dispositif de securite pour scie circulaire
EP2017045A3 (de) * 2007-07-20 2010-12-29 Husqvarna UK Limited Kettensäge
US9599170B1 (en) 2010-06-21 2017-03-21 Hydro-Gear Limited Partnership Electric motor clutch/brake assembly
WO2013086584A1 (en) * 2011-12-15 2013-06-20 Furmanite Australia Pty. Ltd Improvements in machining apparatus
EP3412392A1 (de) * 2017-06-09 2018-12-12 Andreas Stihl AG & Co. KG Handgeführtes arbeitsgerät mit einem werkzeug und einer bremseinrichtung für das werkzeug
US10703006B2 (en) 2017-06-09 2020-07-07 Andreas Stihl Ag & Co. Kg Handheld work apparatus having a work tool and a brake assembly for the work tool
EP3587038A1 (de) * 2018-06-26 2020-01-01 C. & E. Fein GmbH Getriebekopf und handwerkzeugmaschine
CN110640590A (zh) * 2018-06-26 2020-01-03 C.&E.泛音有限公司 传动头和手持式工具机
CN110640590B (zh) * 2018-06-26 2021-06-08 C.&E.泛音有限公司 传动头和手持式工具机
US11167388B2 (en) 2018-06-26 2021-11-09 C. & E. Fein Gmbh Gearhead and handheld power tool
US11374473B2 (en) 2018-11-05 2022-06-28 C. & E. Fein Gmbh EC motor for an electric hand tool and method for producing a rotor for an EC motor
CN116601404A (zh) * 2020-12-10 2023-08-15 赛峰起落架系统公司 具有集成式停泊制动器的致动器

Also Published As

Publication number Publication date
JPS5871109A (ja) 1983-04-27
EP0072610A3 (de) 1984-05-30

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Inventor name: VASSOS, LOUIS J.